Electrical plug connection



May 19, 19.42. K. A. BRAINARD ELECTRICAL PLUG CONNECTION 3 Sheets-Sheet 1 Filed Aug. 2, 1940 INVENTOR. Hindi .KBraz'naJ-rd,

. fiforngy May 19, 1942. K. A. BRAINARD ELECTRICAL PLUG CONNECTION Filed Aug. 2, 1940 3 SheetS -Sh eet 2 r INVENTOR. 728T?! .Efirai narol May 19, 1942.

K. A..BRAINARD v 2,283,177 ELECTRICAL PLUGCONNECTION Filed Aug. ,2, 1940 z Shts-Sheet 3 INVZENTOR. Kenn e2): .Efiraznard,

- BY 7 ATTo EY,

"which forms the outer face of the Patented May 19, 1942 UNITED STATES PATENT OFFICE 2,283,177 I ELECTRICAL PLUG CONNECTION Kenneth A. Brainard,Altaden'a, cam. Application August 2, 1940, Serial No. 349,715

- 7 Claims.

This invention relates to improvements in electrical plug connections and particularly to that type in which the necessary insulated conductor may be secured by simple manual manipulation without the use of tools and by which the plug when inserted in a socket is caused to lie substantially flush with the surface of a surrounding wall to avoid being unintentionally disturbed or disconnected. More particularly this application is a continuation in part, of my companion application filed November 27, 1939, bear-- ing Serial Number 306,349, which on June 10, 1941, matured into Patent-No. 2,244,937, for electrical outlets in which this plug is shown and described. In said prior application the objects and advantages of my; improved plug are fully disclosed and will be further pointed out in the following specification.

In the accompanying drawings, forming part of this specification, Fig. 1 is a side perspective view of my improve'd terminal plug; Fig. 2 is a plan looking at the inner face of the terminal l3 and I4 adjacent to said base and sides. The

g body of the plug thus extends angularly from its base, its axis being substantially normal to the plane of its base or outer face. Extending normally from one of the sides I i; that is obliquely from the plug, is a pair of electrical contact blades I 5 and It as. will be hereinafter described, and extending from the opposite side l2 in the planeof the base or face of the plug is a lip i l, the outer face of which is an extension of the face of the plug. This lip-is used to engage a spring catch ill for removably securing the plug in a receptacle and for simultaneously obscuring the fastening means as will be hereinafter more fully described.

g The body of the plug is preferably made out of insulating material and the electrical contact blades are held rigidly therein in separated parallel relation. The angular side l2 opposite the side fromwhich the blades project is formed with a terminal receptacle 20 which is normally closed by an electrical conductor clamping cover plate plug shown in Fig. '1; Fig. -3 is a section taken on line 3-3 of Fig. 2; Fig. 4 is a section taken on the line 4-4 of Fig. 2; Fig. 5 is a front elevation of one form of a suitable electrical outlet receptacle showing one of my improved terminal plugs inserted therein; Fig. 6 is a section taken on line 66 of Fig. 5, showing two of my improved terminal plugs inserted therein; Fig. 7 is a section taken on line of Fig. 6; Fig. 8 is a top perspective view of the spring catch used for removably holding my improved terminal plug in,

the receptacle; Fig. 9 is a side elevation partly broken away and in section illustrating my improved terminal plug supporting a lamp fixture; Fig. 10 is a side elevation partly in section showing a clock mounted upon my improved terminal plug to be supported thereby; Fig. 11 is a side elevation partly broken away and in section showing a folding hook built into my improved terminal plug for. supporting an object when the hook is turned into unfolded position as shown; Fig. 12 is a side perspective view of an alternate construction of my invention; Fig. 13.18. a vertical section taken approximately on line I 3-l3 of Fig. 12; and Fig. 14 is a perspective view of the electrical conducting cord clamping element employed as a receptacle closing element in the typ of terminal plug shown in Figs. 12 and 13.

My improved terminal plug has a wedge shaped body A defined by a substantially fiat base Ill,

converging opposite sides and I2 extending 2|. This plate is removably secured in closed position under compression by screws 22 or other suitable means. When closed its exposed faces conform with the ODDQsite angular sides of the plug. The electrical conducting cord such as 23,

' which contains the pair of conductors to be connected to the plug is received through the passage 24 in the face of the plug into the terminal receptacle 20 and is anchored securely to the plug by clamping cover plate 2i. This plate has a toothed boss 24 (see Fig. 4), on its inner surface. the teeth of which bite into and impinge the conducting cord to the plug through the tightening of screws. 22. In. making electrical connection with the conductor cord, the end of the cord beyond the portion engaged by the boss is stripped of its outer covering and the two conductors therein thus exposed are spaced apart. Each ofthe inner ends of the contact blades l5 and I6 of the plug is formed with a short angular arm 25 which is firmly secured in the body of the plug and the terminus of this arm is provided plug, a pair of with sharp teeth 26 which face inwardly'toward the inner face of the clamping plate 2|. These teeth are arranged so that when'the insulated conductors of the conducting cord are trained over theteeth and the clamping plate is secured tightly by screws insulation of the cord conductors and make effective electrical contact. Thus when both' conductors of the cord are connected to the pair of contact blades, of 'a plug, electrical connectiqlis are made by properly adjusting the cord 22, the teeth bite through the conductors and by applying the clamping plate as described. Also the clamping plate serves to fasten the body of the conductor cord to the plug ahead of .the conductors so as to relieve pulling strain from the electrical contacts in the plug and allow the plug to be pulled out of its socket by the cord without breaking the electrical connections in the plug.

In Figs. 5 and 6 I have illustrated my improved terminal plug applied to a double form of terminal receptacle, such as is described in my copending application for patent Serial Number 306,919. In this illustration the usual outlet or junction box 30.seated in the wall 3| is provided witha face plate 33 which is constructed with a pair of wedge shaped plug sockets 35 and 36, each of the latter substantially coinciding with the shape of my improved plug so that when the plug is inserted its base or face lies fiush with the outer surface of the face plate leaving no obwhen the plug is inserted in a downward angular,

direction tends to cause the plug to remain in serted and electrically connected without working loose, which is also an advantage. Due to the wedge shape of the plug, downward and direct outward pulling of the conductor cord 23, which leads into the plug also tends to force tllie plug into its socket rather than to loosen the p ug.

The spring catch l8 resembles a cupped washer with a spring arm 40 (see Fig. 8) extending from its rim. This washer is secured by one of the screws 39 by which the face plate 33 is fastened on the outlet box 30, and its spring arm 40 is so shaped and held positioned as to spring into engagement with an edge of the supporting lip I! in a notch 4| and hold the plug inserted in its socket. The plug is released when desired by releasing the spring engaging arm.

In Figs. 12 to 14 inclusive, I have shown a modification of my improved plug for use in the plug receptacle described in my companion application Serial Number 306,349. The outward shape of the plug remains substantially the same as above described. The conducting cord fastening and connecting meansis varied in detail. The wedge shaped body of the plug is formed with a rectangular chamber 45 in. its angular side 46, opposite the side from which the pair of contact blades 41 project. This chamber is closed bythe cord clamping plate 48. The electrical conducting cord 49 enters this chamber through apassage 50 which opens outwardly through the base of the plug and is positioned so that the body of the cord is engaged and held firmly by the serrated boss 5| on the inner surface of the forward end of the clamping plate 48. The heel of the clamping plate opposite the end on which the serrated boss is formed has a pair of laterally projecting spring fastening blades 52 secured thereto, which are adapted to be inserted into a close fitting channel 53 in the body of the plug. The fastening blades 52 are Arranged normally at a slightly obtuse angle to the plane of the inner'wall of the clamping plate 48 so that when the plate is inserted and pressed tightly into a position closing chamber 45, the spring blades 52 tend to forcethe free end of the plate, with its serrated boss 5|, tightly engaging and holding the conducting cord. The electrical contact blades 41 extend right angularly from one of the angular walls i of the plug as in the preferred construction but each is formed with a supporting shank 54 which is threaded into the body and passes freely through one of the blades 52. The fastening elements 54 are placed so that each shank penetrates one of the spring blades'52 and holds the clamping plate 41 in a position closing the chamber' 45 and holding the conductor cord.- A small curved channel 55 is provided inthe'body of the plug adjoining eachshank of the contact blades 47. This passage has its opposite ends connected upwardly into the chamber 45 through the floor of the chamber and its portion between its ends is interceptedby the. threaded shank 54 of one of the contact blades 41 when the blade is screwed through its companion cover fastener 52 and fully into the body of, the plug. A pointed end 56 on the tip of the shank 54 serves to assist in penetrating the insulation on the conductor held in the companion channel 55 so that the screw threads of said shank will impinge the conductor against the wall of the channel and make close electrical contact therewith. a

In Fig. 9 I have shown lamp fixture 60 mounted upon thebase wall of my improved terminal plug, said fixture being supported fiush with the face plate and its weight tendingto hold the plug tightly inserted in its socket. In a similar manner the utility article 6| such as a clock, thermostat or any other article desired is shown mounted upon the plugin Fig. l0. In Fig. 11 I have shown my improved terminal plug constructed with a folding supporting hook 62, recessed when folded into the base wall of the body of the plug. In outstanding position any object such as a clock, for instance can be suspended from the plug on the hook, the weight of the object tending to hold the plug tightly inserted in its socket. These illustrations are typical of many other objects that can be mounted upon the plug with equal effectiveness.

When desired the exposed base of the plug can be provided with a separable surface plate 65, colored or designed to harmonize with the finish of a room in which the plug is used, said surface plate being gibbed at 66 along its side edges to the body of the plug and held at its ends by clips 61, bent or swaged over the body of the plug.

In accordance with the patent statutes, I have described the principles of operation of my invention together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the construction shown is only illustrative and that the invention can be carried out by other means and applied to other uses within the spirit of the invention and within the scope of the following claims.

I claim:

l. A wedge shaped plug body for use in cooperation with a wedge shaped wall socket, said plug body having a base and opposite converging sides and a connector mounted upon the plug body normal to and projecting from one of said sides, said plug body being insertable in the wall socket at anoblique angle to the plane sides, and

.plug body having tending outwardly axis of the connector to assist in holding the plug body inserted with said base flush with the outer surface of the wall socket.

2. A wedge shaped plug body for use in cooperation with a wedge shaped wall socket, said plug body having a base and opposite converging sides, a connector mounted upon the plug body normal to and projecting from one of said a fastening lip in extension and in the plane of said base by which the plug bodycan-be engaged with the socket, said plug body being insertable in the wall socket at an oblique angle to the plane of said base and with said connector entering an inner wall of the socket longitudinally of the axis of the connector to assist in holding. the plug body inserted with said base flush with the outer surface of the wall socket.

3. A wedge shaped plug body for use in a wedge shaped wall socket, said plug body having a base and opposite converging sides and a pair of electrical contact terminals'entering the plug body normal to andextending' outwardly from one of said converging sides, insertable in said wall socket at an oblique angle to ithe plane of said base and in longitudinal alignment with said connecting terminals and said base having a passage adapted to receive an electrical conductor into connection with said contact terminals in 'the plug body.

4. In a, structure as defined in claim 3, the means therein for fastening said conductor to prevent outward pulling strain upon the connections between the conductor and the inner ends of the contact elements. 5. A wedge shaped plug body for use in a wedge shaped wall socket, said plug body having Va'base, a pair of opposite converging sides and a chamber entering one of said sides, a pair of electrical contact terminals normal to and extl eirinner ends entering said chamber and beends of the contact terminals, and a clamping said plug body being ing pointed, an electrical conductor entering said chamber through the base ofthe plug body having branches extending over the" pointed inner plate closing said chamber and impinging said conductor branches upon said pointed terminal ends and engaging and holding said conductorto prevent outward pulling strain by the conductor upon theconnections between said branches and said pointed terminal ends.

6. A wedge shaped plug body for use in a wedge shaped wall socket, said plug body having a base, a pair of Opposite. converging sides and a chamber entering one of said sides, a pair of electrical contact terminals normalto and extending outwardly from one of said converging sides with their inner ends entering said body, an electrical conductor having branches entering 'said chamber through said base, a cover element over said chamber, and means interposed be- .tween the .cover element and the contact terminals for connecting said branches to the con-.

tact elements.

7. A wedge shaped plug bodyfor use in a wedge shaped wall socket, said plug body having a base, apair of opposite converging sides and a pair of electrical contact terminals entering the plug body-normal to and extending outwardly from one of said converging-sides, said base having a passage adapted to receive'an electrical conductor into connection with said contact terminals in the'plugbody, and said bodyhaving a fastening lip said base by'which the plug body can be engaged with the socket, said plug body being insertable in the wall socket at an oblique angle to the plane of said base and with said contact terminals entering an inner side of said socket from one of said sides with longitudinally of the'axes of said terminals w assist in holding the plug body inserted with said base flush with the outer surface of the wall socket.

KENNETH A. BRAINARD.

in extension and in' the plane of 

